Adjustable cam followers for zigzag sewing machines



Oct. 10, 1961 5 HERBsT AL 3,003,366

ADJUSTABLE CAM FOLLOWERS FOR ZIGZAG SEWING MACHINES Filed Nov. 17, 1958 INVENTORS Edward J. Herbs! rif en R. Mulle I United States Patent 3,003,363 Patented Oct. 10, 1961 ADJUSTABLE CAM FOLLOWERS FOR ZIGZAG SEWING MACHINES Edward J. Herbst, South Plainfield, and Griifen R. Muller, New Brunswick, NJ., assignors to The Singer M2111]! facturing Company, Elizabeth, NJ., a corporation of New Jersey Filed Nov. 17, 1958, Ser. No. 774,175 6 Claims. (Cl. 74-569) This invention relates to improved adjustable cam followers adapted for use with zigzag sewing machines, andthe primary object of the invention is to provide an improved device of this character.

Another object of the invention is to provide an improved cam follower mechanism by use of which adjustments can be made to compensate for minor dimensional variations due to additive manufacturing tolerances and/ or due to wear.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readly understood by those skilled-in the art.

In the drawings:

FIG. 1 is a fragmentary view of a zigzag sewing machine equipped with an adjustable cam follower embodying the present invention,

FIG. 2 is a view similar to FIG. 1, except that a portion is in section and the cam follower is shown adjusted to a different position than is shown in FIG. 1,

. FIG. 3 is a fragmentary elevational view taken substantially on the line 3-3 of FIG. 1, and

FIG. 4 is an enlarged perspective view of an eccentric cam follower adjustor forming part of the adjustable cam follower mechanism shown in FIGS. 1 to 3.

Referring more specifically to the drawings, the invention is disclosed as embodied in a zigzag sewing machine of a type similar to that shown in United States patent application SerialNo. 471,766, filed November 29, 1954, now United States Patent No. 2,862,468. This previously filed United States patent application, among other things, discloses an ornamental stitch forming means having a cam mechanism similar to the cam mechanism of the present application. One portion of the mechanism, whichis common to both disclosures, includes a cam driven connection or pitman 16 one end of which (not herein shown) is movably mounted in a manner to allow the pitman 16 to execute both endwise and lateral movement. The free or distal end 17 of the pitman 16 tumably carries a motion integrating plate 1 8 having a front face 19 and a rear face 21. In order to bias the pitman 16 and the plate 18 in the direction indicated by the arrow 22 of FIGS. 1 and 2, a two-armed pivotal member 23 is turnably mounted on a screw 24 which in turn is mounted on the sewing machine frame. The member 23 is biased to turn in a counterclockwise direction about the screw 24 by a spring 26 attached to one arm 27 of the member 23. The free end of the other arm 28 of the member 23 presses against the rear face 21 of the plate 18. Another portion of the mechanism, which is com mon to both disclosures, includes a cam disk 36 having a handle 37 rotatably mounted by means of a shoulder screw 38 on a cylindrical stud (not shown).

The new and improved adjustable cam follower 41 of the present invention comprises a lever made of two parts, namely, parts 43 and 44. The first part 43 is substantially U-shaped in form and has a short arm 46 and a long arm 47 connected by a reach 48. Both of the arms 46 and 47 are apertured, as at 49, whereby part 43 is pivotally carried on an upright post 51, of which the lower end is secured to a portion 52 of the sewing machine frame. The free end of-the arm 47 carries an upstanding elongated cam-engaging follower finger 53 and the portion of the arm 47 between the aperture 49 and the reach 48 is provided with a threaded hole 54 which receives the lower end of a screw 56.

The upper face of the arm 47 is contacted by the lower face of the second part 44, and the second part 44, which is in the form of an elongated plate, is apertured, as at 57, and is thereby pivotally mounted'on the upright post 51. One end of the part 44 is provided with a horizontally extending finger 58 adapted to engage the front face 19 of the plate 18. The other end of the part 44 is bifurcated to form an open-ended slot 59 bounded on two sides by tines 61 and 62 which tines straddle the external eccentrically positioned surface 63 of a cam-follower adjustor 64.

The adjustor 64 is provided with a central unthreaded hole 66 adapted to receive the shank of the screw 56 and the upper end of the adjustor 64 carries a concentrically positioned wrench receiving head 67 by means of which the adjustor 64 may be turned about the screw 56. Reference to the drawings shows that the head 67 is larger than the eccentric 63 and also larger than the space formed by the slot 59 between the tines 61 and 62. Also the axial length of the eccentric 63 is less than the thickness of the part 44. Because of these dimensions, tightening the screw 56 causes the lower surface 68 of the adjustor 64 to be pressed against the upper surface of the tines 61 and 62, thereby clamping the tines 61-62 to one end of the arm 47 of the part 43. The parts 43 and 44 are prevented from moving upwardly on the post 51 by a screw held collar 65. The portion of the arm 47 located between the aperture 49 and the follower finger 53 is provided with a threaded hole 69 extending from the top to the bottom of the said arm 47. Also, the portion of the part 44 located between the aperture 57 and the finger 58 is provided with an oversized hole 72 extending from the top to the bottom of the part 44. A headed holding screw 73 passed downwardly through the hole 72 is screwed into the threaded hole 69. The diameter of the hole 72 is considerably larger than the diameter of the shank of the screw 73. This allows the part 44 to move with respect to the arm 47 of the part 43 when the screws 73 and 56 are loosened. Also, the head of the screw 73 is large enough to always cover the hole 72 regardless of the adjustment between the parts 43 and 44. In order to prevent binding, the upper end of the aperture 57 in the part 44 is slightly frusto conical as indicated by the numeral 74.

In operation the hereinbefore described mechanism functions as follows. When the cam disk 36 rotates, the mountains and valleys on the edge of the cam disk 36 cause the cam follower finger 53 to oscillate the U-shaped part 43 about the post 51. Under normal operating conditions, the screws 56 and 73 will be tightened sufliciently to clamp the part 44 to the arm 47 of the part 43. Because of this, all movements of the cam follower finger 53 will be imparted to the finger 58 which is engaged by the front face 19 of the plate 18. Thus, movements of the plate 18 and the pitman 16 are governed by rotation of the cam disk 36. Since the pitman 16 may be moved both longitudinally and laterally, it will be understood that the finger 58 may engage the face 19 at various locations, as for example, the two diiferent locations 71' and 71" shown in FIGS. 1 and 2.

In addition to the above, the cam follower 41 may be adjusted to compensate for minor dimensional variations loosening the screw 56. Then the adjustor 64 is turned by'means of a wrench (not shown) applied to the head 67., the, adjuster 6.4 causes the eccentric surface 6,3; to turn the part, 44, about the. post 51 relative, to the arm 47. of the. part 43... turning of the part 44 relative tothe. part, 43 causes. the fingers 5358 to move closer to one anotheron-tomeve farther apart as may be desired; After adjustments are made, the screws 56 and 7J3t are tightened. in, ordertomakecertain that there will be no relafiyemovement; between the parts 43- and 44. ;.Haying thus,descr ibed the nature of the invention, what. we claim hereinisz. r

1. adjustable. cam follower device for sewing machine said cam follower device comprising, a first part pivotallycarried by said sewing machine, a second part also pivotally; carried by said sewing machine, a follower formed on one of said parts, a follower means formed on the other of said parts, an eccentric carried by one of said parts, means carried by the other of said parts, for engaging said eccentric, means for adjusting said eccentric and thereby: pivotally adjustingone of said parts with, respect tothe other of said parts and means 4. An adjustable cam follower for zigzag sewing machines, said cam follower comprising an upright post carried by said sewing machine; a U-shaped lower part pivotally carried on said upright post, said lower part having a first and a second arm connected by an upwardly extending reach, one end of said secondann being provided with a threaded hole; an: upstanding cam follower formed. on .the end of said. second arm. which is remote from said threaded hole; a screwthreaded into: said'hole in said second'arm; an-adjustor turnably. mounted on said screw, a wrench receiving head formed on said adaptor; an eccentric'sm'face formed on said adjustor; an elongated plate-shapediupper part pivotally carried on said upright post; a. cam follower formed on one end of said for securing one of. said parts'to the'other of said parts.

2. An adjustable. cam follower device for sewing machines, saidcam follower device comprising, a first part pivotally carried by said sewingmachine and said first part having two ends, a second part also having two ends and also; being pivotally carried by said sewing machine, a follower finger formed on oneend of said first part, a follower finger formed on one end of said second part,

' an eccentric carried by the. other end of said first part,

eccentric engaging means carried by the other end of said, second 'part, wrench receiving means for adjusting said, eccentric and thereby pivotally adjusting one of said parts'with respect to the other of said parts, and means for locking one. of said parts to the other of said parts in selected adjusted position, i

upper part; and a pair of tinesv formed on the other end of said upper part, said tines defining an open-ended slot adapted to receive the said eccentric, surface. formed on said adjustor.

5. In a sewing machine, a cam, meansfor turning, said cam, cam driven connections adjacent to said cam, and cam follower means interposed between said camand. said cam driven connections to transmit intelligence. from said cam driven connections, said cam. followencomprisinga pair of flat members disposedin faceto-face relation and arranged to be pivoted with. one engagingsaid cam and the other engaging said .c ani' driven connections and' means providing for pivoting one of said flat membe rs relatively to the other of said'fiat members to ac,- commodate' variations in the spacing between the cam and the cam driven connections. i

6. An adjustable cam follower device for sewing n'ia chines, said cam follower device comprising, a first. part pivotally carried by said sewing machine, a second part also pivotally carried by said sewing machine, a follower means formed on one of said parts, a follower means formed on the other ofsaid parts, an. eccentric carried by one of said parts, means carried by the otherof said parts for engaging said eccentric, means. for adjusting said r 3. An. adjustable cam follower device for sewing machines, said cam follower device comprising, a U-shaped part pivotally carried by said sewing machine, a second partalso. pivotally carried'by said sewing machine, a follower'fi'nger formed on said. U-shaped part, a follower finger formed on said second part, an eccentric cam follower adjustor supported by said U-shaped part, an eccentric en'gaging means carried by the second part, means for adjusting said eccentric and thereby pivotally adjusting, one of said parts with respect to the other of said parts, and clamping means for clamping said second part to, said U-shaped part.

eccentric and thereby pivotally adjusting one of said parts with respect to the other of said parts, and a plii rality of screws for securing one of' said, parts to the other of said parts.

References Cited in the file ofthispatent UNITED STATES PATENTS 

